Abstract: 【Objective】 Based on metagenomics，the effects of Pediococcus pentosaceus 368 on the fecal microbial community structure and gene function of Dusa pigs were explored，in order to reveal the potential prebiotic function of Pediococcus pentosaceus 368 and theoretical basis for its mechanism of action. 【Method】 Dusa pigs with similar body weight were selected and randomly divided into a control group（FC）and an experimental group（FA）according to the principle of gender balance，with 2 replicates in each group and 5 Dusa pigs in each replicate. The same basal diet was fed，and Pediococcus pentosaceus 368 was added to the drinking water of the FA group. The experimental period was 28 d. On the days of the start and end of the experiment，the pigs were weighed after fasting for 12 h，and the feeding situation was recorded. After the end of the experiment，the average daily weight gain，average daily feed intake and feed to weight ratio were calculated. After the end of the experiment，3 Dusa pigs were randomly selected from each replicate and fresh feces were collected. The effect of Pediococcus pentosaceus 368 on the fecal microbial community structure and gene function of Dusa pigs was analyzed by metagenomic sequencing technology. 【Result】 The average daily feed intake and average daily weight gain of Dusa pigs in the FA group were higher than those in the FC group，and the feed to weight ratio was lower than that in the FC group，but the difference was not significant（P>0.05）. The results of Alpha diversity index analysis showed that the Shannon index of the FA group was significantly higher than that of the FC group（P˂0.05， the same below），and the Simpson index was extremely significantly higher than that of the FC group（P˂0.01）. The results of Beta diversity analysis showed that the samples of the FA and FC groups had both overlapping and separated parts in the coordinate space，and the microbial community of the FA group had some changes while maintaining similarity. At the genus level，the genus Prevotella_copri had the highest relative abundance in both the FA and FC groups. The results of LEfSe analysis showed that when LDA>3.0 ，14 biomarkers were obtained in the FA group and 6 biomarkers were obtained in the FC group. KEGG database annotation analysis found that when LDA>3.0，the 2 signal pathways of signal transduction and amino acid metabolism annotated to genes only in the FA group. CAZy database annotation analysis found that at the level 1，the number of genes annotated to the auxiliary oxidoreductase signaling pathway in the FA group was significantly higher than that in the FC group；at the level 2，there were 30 signaling pathways with significant differences in the number of genes annotated between the FA and FC groups，and the number of genes annotated to 26 signa-ling pathways in the FA group was significantly up-regulated compared with the FC group. When LDA>2.0，4 related genes were screened out，of which CBM61，CT58 and GH13_9 belonged to the FA group，and GH0 belonged to the FC group. CARD resistance gene analysis results showed that when LDA>2.0，3 types of differential resistance genes were screened out，and the resistance genes in the FC group were mainly enriched in carbapenem hydrolyzing β-lactamase，and the resistance genes in the FA group were mainly enriched in vga type ABC F potein and glycopeptide resistance gene clusters. 【Conclusion】 Adding Pediococcus pentosaceus 368 to drinking water can improve the growth performance of Dusa pigs and change the composition of their fecal microbial community，increase the relative abundance of dominant bacteria such as Firmicutes and Clostridiales. It can also increase the relative abundance of family genes such as GH13， GH96 and GH84 related to complex carbohydrate metabolism，Pediococcus pentosaceus 368 may have a potential probiotic effect in promoting the expression of bacteria and enzymes related to complex carbohydrate metabolism.